I am still using Struts 1.0.2 since 1.1 is just beta and we don't want to move to 1.1 until it is production-ready. We will then use the Validator that is bundled with 1.1. For now, though, we use the ActionForm classes that you mention in part to do what you mention. I believe that ActionFormBean is a class used internally by Struts and is not something you have to extend or otherwise concern yourself with. If you extend the ActionForm classes as you describe, thinks should work as you describe.
An interesting resource in seeing the different parts of Struts is at http://rollerjm.free.fr/pro/Struts.html
and it talks a little about ActionForm and ActionFormBean. The names are confusing.